Wang Jiahui, Li Yan, Ling Xianzhang, Yang Ping, Zhao Yingying
College of Civil Engineering, Nanjing Forestry University, Nanjing 210037, China.
China 19th Metallurgical Group Corporation Limited, Chengdu 610031, China.
Materials (Basel). 2023 Feb 11;16(4):1520. doi: 10.3390/ma16041520.
To investigate the dynamic stability of natural subgrade filler (NSF) and fiber-binder reinforced subgrade filler (RSF) under cyclic load after freeze-thaw (FT) cycles, a triaxial test was conducted to determine the correlation between cumulative plastic strain (CPS) and the quantity of loading cycles, as well as the evolution law of dynamic strength and critical dynamic stress (CDS) with different FT cycles. The CPS change in the NSF and RSF shows three states (stable, critical, and destructive) with increasing vibration times. However, both fillers have different failure forms, and the curve shapes of the CPS with loading cycle quantities before and after failure are also different. With the number of FT cycles increasing, the requisite dynamic stress threshold for NSF specimen failure decreases continuously. After three FT cycles, the anti-cumulative deformation ability of the NSF decreases by approximately 32%. The anti-cumulative deformation abilities of the NSF after seven and nine FT cycles, respectively, are similar. The amelioration measures could significantly enhance the FT resistance of the NSF. After zero, one, three, five, seven, and nine FT cycles, the requisite dynamic stress threshold for the RSF to reach destruction is increased 1.52, 1.89, 1.98, 2.32, 2.2, and 2.45 times, respectively, compared to that of the NSF. A mechanical model of critical dynamic stress of the NSF and RSF that considers the FT cycle was obtained using a multivariate nonlinear regression method.
为研究冻融（FT）循环后天然路基填料（NSF）和纤维-粘结剂增强路基填料（RSF）在循环荷载作用下的动力稳定性，进行了三轴试验，以确定累积塑性应变（CPS）与加载循环次数之间的相关性，以及不同冻融循环次数下动力强度和临界动应力（CDS）的演化规律。随着振动次数增加，NSF和RSF的CPS变化呈现出三种状态（稳定、临界和破坏）。然而，两种填料具有不同的破坏形式，破坏前后CPS随加载循环次数的曲线形状也不同。随着冻融循环次数的增加，NSF试样破坏所需的动应力阈值不断降低。经过三次冻融循环后，NSF的抗累积变形能力降低了约32%。NSF在七次和九次冻融循环后的抗累积变形能力相似。改善措施可显著提高NSF的抗冻融能力。与NSF相比，RSF在零次、一次、三次、五次、七次和九次冻融循环后达到破坏所需的动应力阈值分别提高了1.52、1.89、1.98、2.32、2.2和2.45倍。采用多元非线性回归方法得到了考虑冻融循环的NSF和RSF临界动应力力学模型。
